[llvm] [LiveDebugVariables] Add basic verification (PR #79846)

[Adrian Prantl via llvm-commits]

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@@ -492,6 +492,13 @@ class UserValue {
   /// Return DebugLoc of this UserValue.
   const DebugLoc &getDebugLoc() { return dl; }
 
+  void verify() const {
+    for (auto I = locInts.begin(), E = locInts.end(); I != E; ++I) {
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adrian-prantl wrote:

```suggestion
    for (auto I : locInts) {
```

https://github.com/llvm/llvm-project/pull/79846